"Classic," the breakthrough hit by the duo MKTO, has been certified platinum as the group's first million-selling hit.

The track, which peaked at No. 21 on the Billboard 200, has also been certified two-times platinum in Australia, where the "MKTO" album hit No. 1 (it peaked at No. 31 on the Billboard 200 in the U.S.).

The group's Tony Oller tells us that he and Malcolm Kelly, who met on the set of TeenNick's "Gigantic" series, are stoked by how well their music has been received so far:

"Just being able to get music out there to not only be enjoyed, but the response was just as well as we hoped for, if not more. You never go into anything expecting; you hope for the best, expect the worst... But I think the response, and 'Classic' going platinum, I feel like is a good sign that we're doing something right. The response has been great. It's just overwhelming at times to see how much it's grown in just two years. It's incredible. Definitely didn't expect it, but very excited and happy it did and excited for more to come."

MKTO has released a new single from the album, "American Dream," and kicks off its first ever headlining tour on June 27 in the Detroit suburb of Royal Oak.